1. Field of the Invention
The invention relates to a rocker valve with pneumatic pre-control, including a housing with the pressure means connections, in which housing at least one rocker is arranged which is movable between two final positions about an axis and works together with at least one sealing surface for at least one valve seat of a pressure connection, where one handle of the rocker can be impacted with a pre-control pressure via a pre-control connection and the rocker in one final position locks the valve seat tightly and in the other final position opens to at a maximal diameter.
2. The Prior Art
A rocker valve of this type is, for example, known through a structural design by Samsomatic Automationssysteme GmbH. In so doing, the basic position, in which the supply connection and the working connection are isolated from one another, is maintained through elasticity and the switching, or in other words, the opening of the connection of supply and working connection or the closing, occur pneumatically pre-controlled. The pivotal axis of this arrangement is given by the simple thickening of an elastomer shape sealing, with which the security of the sealing and because of the additional mechanical load of the sealing element also the longevity of the valve can be negatively influenced. Besides this, the valve is kept closed merely through the elasticity and thus has pressure-dependent characteristics; it is only usable up to a predetermined maximum pressure.
Beyond this, rocker valves have been built in various other arrangements, such as the lifting anchor model of Buckert. In this model, a rocker is kept through elasticity in a closing position (supply connection and working connection isolated from one another) and the switching occurs via a lifting magnet which tilts the rocker against the effect of the spring about the pivotal point in the open position. Again, the valve is held closed by merely the elasticity and thus has pressure-dependent characteristics; it is only usable up to a predetermined maximum pressure. Besides this, the valve requires a lot of space because of the electromagnet necessary for switching.
For this reason, it was the object of the present invention to create a rocker valve that is operable purely via pressure means, which can be implemented in a versatile way with as much simplicity of construction and space-savings as possible, is adjustable to a variety of uses, and offers the highest possible operational security through the best possible sealing of the connections and precision as well as short switching times.
This object is solved according to the invention in that, at least on the side of the rocker with a working connection, a sealing is provided between the edge of the rocker and the inner wall of the housing, through which on the side of the rocker with respect to the axis as well as the plane of the rocker a chamber with at least two connections is formed, which chamber is preferably separated from at least one other connection on the opposite side with respect to the rocker plane. In this way the further connections remain secure and tightly separated from both of the other connections on the other side of the rocker, and a precise switching of the valve can be guaranteed, despite rapid switching times and, at the same time, flat construction in regard to the diameter of the opening. Due to the sufficiently small pivotal movements of the rocker, the valve according to the invention can be built to be very small and flat, and can exhibit a layered construction which, in both assembly and repair, allows for the very simple operation of work to be done.
According to the advantageous embodiment of the invention, it is provided that, on both sides of the rocker, a sealing element is provided between the edge of the rocker and the inner wall of the housing; in this way, on each side of the rocker one chamber with at least two connections is formed which connections are preferably separated by at least one further connection on the side that lies on the opposite side with respect to the rocker plane. In this way, the versatility of the valve according to the invention is further expanded, since with this structural design, while maintaining the speed and precision of switching, many different occupancies of the connections and thus many uses are made possible.
According to one embodiment of the invention, two working connections are present from which, in each of both of the final positions of the rocker, one working connection each is covered by the rocker and the sealing surface, whereby one working connection is separable by the rocker from one supply connection and the second working connection is separable by the rocker from one ventilation connection. Thus, a valve construction with the smallest impairment spaces is made possible which guarantees in all embodiments, also upon activation of the pressure means and even for large outlet cross-sections, rapid switching times and precise sealing function.
According to a further embodiment of the invention, an NO-valve (normal condition, that is, without pre-control, open) can be realized in a simple manner in that the effective area, surface of application for the supply pressure against the movable parts of the valve is larger than the area of the outlet of the second working connection connected to the ventilation connection.
To realize a 2/2-way valve in a simple manner and with the above-mentioned advantages, provided according to another embodiment of the invention, is that, on merely one side of the rocker, two connections are provided in one chamber, which chamber is limited by the elastic sealing element extending from the edge of the rocker to the inner wall of the housing.
If at least two rockers are provided in on housing as connected parallel to one another, a very rapid and precise 4/2 or 5/2 way valve of a small structural height and all of the other already-mentioned advantages can be manufactured.
Advantageously, it is provided that the rocker is positioned substantially symmetrical about the axis of rotation. This facilitates the assembly of the valve and its reconstruction in different embodiments and the arrangement with respect to the switching pressures and times. Slight deviations in the total symmetry with respect to the area ratios of the pressure means outlets and effective areas for the application of the pressures are possible for the arrangement of a precise switching behavior, for example, for achieving a switching hysteresis.
To advantageously guarantee the easy mobility of the rocker and rapid switching times along with simple construction and assembly, the outer edge of the rocker is, at least over a part of its length, distanced from inner wall of the housing, and at least one sealing element extending between the edge of the rocker and the inner wall of the housing, preferably an elastomer sealing element, is provided.
If, according to a further embodiment, the sealing element is arranged as one piece with at least one sealing surface for the connection is preferably as one piece with both sealing surfaces, and extends to both sides of the rocker, an especially simple construction with minimal number of parts is thus provided which furthermore, is very functionally secure and has a long life.
To obtain a very flatly built structural design which can also be simply placed onto existing connection plates, and on which again pre-control or magnet control valves can be placed, it is provided that the supply connection, the working connections and the ventilation connection are arranged in the same half space with respect to the plane of the rocker, where the supply connection and the ventilation connection lie opposite one another with respect to the axis of rotation of the rocker, and that the pre-control connection is located in the half space that lies opposite the rest of the connections with respect to the plane of the rocker.
According to an advantageous embodiment of the rocker valve according to the invention, it is provided that, between the handle of the rocker and the housing, a spring element is inserted into this handle of the rocker with a force, by which the rocker in the pressure-less condition of the rocker valve is held in a defined final position and also the movement of the rocker is supported. Even at a first-time switching or in transitional conditions during the switching, unstable positions are prevented and thus the largest possible switching security and precision is guaranteed. Also, the spring element supports the effect caused by the pressure means on the rocker and, in such a way, can support, for example, the closing effect.
The same advantageous effect can be achieved by a sealing element which prefers a final position and biases the rocker into this final position, where the sealing element is preferably arranged in the shape of a crimped elastomer membrane.
According to a special, advantageous embodiment of the invention, the pre-control connection opens on the side of the handle of the rocker which separates the working connection from the ventilation connection. In so doing, the lever action upon application of the pre-control pressure to overcome the pressure at the supply pressure connection can have the optimal effect.
If, according to a further embodiment of the invention, an access is provided for the supply pressure into the housing space and lying opposite the housing space into which the supply pressure connection and one of the working connections open is provided, a structural design of the valve with the highest possible pressure independence is ensured. The supply pressure which also, on the side lying opposite the supply connection and its corresponding working connection, has an effect on the rocker, compensates for the torque that has an effect on the rocker, so that it can be held securely by means of slight, additional forces in the closing position. Thus, no principle maximal pressure with respect to the secure functioning of the valve according to the invention exists and, depending on the area ratio of both handles of the rocker including the corresponding sections of the sealing element, the pre-control pressure necessary for opening the valve can be equal to the supply pressure or equal to a fraction of the supply pressure.
In a manner that is structurally simple and does not influence the structural size of the valve, the above-mentioned torque compensation can be achieved in that, in the handle of the rocker which separates the supply connection from the working connection and/or the corresponding section of the sealing element, at least one through-opening is provided in the housing space lying opposite the supply connection.
If, advantageously, the axis of rotation of the rocker is defined by at least one crosspiece of the housing, onto which the rocker lies, preferably by two crosspieces lying opposite one another, between which the rocker is inserted, the rocker has an exactly defined axis of rotation through this direct housing support. This results in a better sealing, an even more precise switching and, through minimization of the mechanical service conditions of the sealing element, a lengthening of the life of the valve. Of course, in order to allow for the deflection of the rocker, there must always be enough play between the rocker and the crosspieces.
If that or every crosspiece is sealed off through a section of a circling sealing of the sealing element, a simple structural design, a secure installation and a secure functioning is guaranteed.
The sealing can be arranged, according to an advantageous embodiment, in the area of the crosspiece as a lip sealing with sealing lips bent away from the crosspiece. Therefore, the pre-stress necessary for the best possible sealing in the area of the crosspiece does not cause any congestion of the sealing and thus exercises only a minimal force onto the rocker itself. The power and torque ratios at the rocker are mainly determined through the pneumatic pressures and are not negatively influenced by the pre-stress of the sealing.
According to a further advantageous embodiment, also the axis of rotation of the rocker can be defined by at least one crosspiece of at least one of the sealing elements, which crosspiece is taken up in corresponding cavities of the housing, preferably through two crosspieces on opposite sides of the sealing element. This allows for a somewhat more flexible storage with, in some cases, an easier tilting of the rocker.
In order to hold the rocker securely and to guarantee a stable connection between the rocker and the sealing element, a preferred embodiment has the rocker embedded in a one-piece sealing element.
If there are fewer requirements, a more simply manufactured variation is imaginable in which the rocker is mounted onto the surface of a one-piece sealing element, preferably on the side opposite the valve seats to be sealed off, and fixed onto it.
Equally simple in terms of manufacturing is an embodiment of the rocker valve according to the invention, in which the rocker is embedded between two separate sealing elements, where the sealing elements are preferably held at a distance to one another in the insertion area by means of one housing crosspiece or an additional part with preferably the same thickness as the rocker. In so doing, the additional, distancing part or the equivalent crosspiece in the housing ensures a minimization of the mechanical load of the sealing element as well as their better seating and thus ensures the sealing effect as well as an increased mobility of the rocker. The increased mobility can be even more improved by the layering of the side of the sealing element facing the rocker with a lubricant or a sliding layer.
Advantageously, the space between both of the sealing elements is ventilated, so that no negative influence of the power and torque ratios on the rocker can occur.
According to another embodiment, the rocker has, at least in the area of the edge, a cavity in which the edge of the sealing element facing away from the housing is held as inserted and sealed off. In so doing, based on the rocker that is kept free from the sealing element or other elastomer material, a precisely defined situating of the rocker in the area of the crosspiece is guaranteed.
For simpler manufacturing and maintenance it is, thus, advantageously provided that the rocker consist of two plates lying over and directly against one another preferably, in the area of the crosspiece, where the outer edges of the plates are at a distance to one another and the inner edge of the sealing element is inserted in between like a sandwich.
A structural design is advantageous during assembly and repair which includes a frame as an additional part, which frame also has a bearing for the axis of rotation of the rocker. At the same time, the axis of rotation of the rocker is exactly defined, through which a secure sealing effect and thus, highest functional security is guaranteed.
The sealing effect and thus the functional security of the valve according to the invention can be optimally guaranteed in that the rocker itself has such an expansion that every opening of every working connection is covered.
In an advantageous manner, a rocker valve can be used according to one of the previous paragraphs as a simple, cheap and functionally secure logic element.
The invention will be better understood by reference to the attached drawings taken in conjunction with the following discussion.